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Kazanietz MG, Cooke M. Protein kinase C signaling "in" and "to" the nucleus: Master kinases in transcriptional regulation. J Biol Chem 2024; 300:105692. [PMID: 38301892 PMCID: PMC10907189 DOI: 10.1016/j.jbc.2024.105692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 02/03/2024] Open
Abstract
PKC is a multifunctional family of Ser-Thr kinases widely implicated in the regulation of fundamental cellular functions, including proliferation, polarity, motility, and differentiation. Notwithstanding their primary cytoplasmic localization and stringent activation by cell surface receptors, PKC isozymes impel prominent nuclear signaling ultimately impacting gene expression. While transcriptional regulation may be wielded by nuclear PKCs, it most often relies on cytoplasmic phosphorylation events that result in nuclear shuttling of PKC downstream effectors, including transcription factors. As expected from the unique coupling of PKC isozymes to signaling effector pathways, glaring disparities in gene activation/repression are observed upon targeting individual PKC family members. Notably, specific PKCs control the expression and activation of transcription factors implicated in cell cycle/mitogenesis, epithelial-to-mesenchymal transition and immune function. Additionally, PKCs isozymes tightly regulate transcription factors involved in stepwise differentiation of pluripotent stem cells toward specific epithelial, mesenchymal, and hematopoietic cell lineages. Aberrant PKC expression and/or activation in pathological conditions, such as in cancer, leads to profound alterations in gene expression, leading to an extensive rewiring of transcriptional networks associated with mitogenesis, invasiveness, stemness, and tumor microenvironment dysregulation. In this review, we outline the current understanding of PKC signaling "in" and "to" the nucleus, with significant focus on established paradigms of PKC-mediated transcriptional control. Dissecting these complexities would allow the identification of relevant molecular targets implicated in a wide spectrum of diseases.
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Affiliation(s)
- Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| | - Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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2
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Kalinina EV, Novichkova MD. S-Glutathionylation and S-Nitrosylation as Modulators of Redox-Dependent Processes in Cancer Cell. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:924-943. [PMID: 37751864 DOI: 10.1134/s0006297923070064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 09/28/2023]
Abstract
Development of oxidative/nitrosative stress associated with the activation of oncogenic pathways results from the increase in the generation of reactive oxygen and nitrogen species (ROS/RNS) in tumor cells, where they can have a dual effect. At high concentrations, ROS/RNS cause cell death and limit tumor growth at certain phases of its development, while their low amounts promote oxidative/nitrosative modifications of key redox-dependent residues in regulatory proteins. The reversibility of such modifications as S-glutathionylation and S-nitrosylation that proceed through the electrophilic attack of ROS/RNS on nucleophilic Cys residues ensures the redox-dependent switch in the activity of signaling proteins, as well as the ability of these compounds to control cell proliferation and programmed cell death. The content of S-glutathionylated and S-nitrosylated proteins is controlled by the balance between S-glutathionylation/deglutathionylation and S-nitrosylation/denitrosylation, respectively, and depends on the cellular redox status. The extent of S-glutathionylation and S-nitrosylation of protein targets and their ratio largely determine the status and direction of signaling pathways in cancer cells. The review discusses the features of S-glutathionylation and S-nitrosylation reactions and systems that control them in cancer cells, as well as their relationship with redox-dependent processes and tumor growth.
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3
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Protein kinase C epsilon promotes de novo lipogenesis and tumor growth in prostate cancer cells by regulating the phosphorylation and nuclear translocation of pyruvate kinase isoform M2. Exp Cell Res 2023; 422:113427. [PMID: 36400183 DOI: 10.1016/j.yexcr.2022.113427] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 11/17/2022]
Abstract
Protein kinase C epsilon (PKCε) belongs to a family of serine/threonine kinases that control cell proliferation, differentiation and survival. Aberrant PKCε activation and overexpression is a frequent feature of numerous cancers. However, its role in regulation of lipid metabolism in cancer cells remains elusive. Here we report a novel function of PKCε in regulating of prostate cancer cell proliferation by modulation of PKM2-mediated de novo lipogenesis. We show that PKCε promotes de novo lipogenesis and tumor cell proliferation via upregulation of lipogenic enzymes and lipid contents in prostate cancer cells. Mechanistically, PKCε interacts with NABD (1-388) domain of C-terminal deletion on pyruvate kinase isoform M2 (PKM2) and enhances the Tyr105 phosphorylation of PKM2, leading to its nuclear localization. Moreover, forced expression of mutant Tyr105 (Y105F) or PKM2 inhibition suppressed de novo lipogenesis and cell proliferation induced by overexpression of PKCε in prostate cancer cells. In a murine tumor model, inhibitor of PKM2 antagonizes lipogenic enzymes expression and prostate cancer growth induced by overexpression of PKCε in vivo. These data indicate that PKCε is a critical regulator of de novo lipogenesis, which may represent a potential therapeutic target for the treatment of prostate cancer.
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4
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Kawano T, Inokuchi J, Eto M, Murata M, Kang JH. Protein Kinase C (PKC) Isozymes as Diagnostic and Prognostic Biomarkers and Therapeutic Targets for Cancer. Cancers (Basel) 2022; 14:5425. [PMID: 36358843 PMCID: PMC9658272 DOI: 10.3390/cancers14215425] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/02/2022] [Accepted: 11/02/2022] [Indexed: 08/05/2023] Open
Abstract
Protein kinase C (PKC) is a large family of calcium- and phospholipid-dependent serine/threonine kinases that consists of at least 11 isozymes. Based on their structural characteristics and mode of activation, the PKC family is classified into three subfamilies: conventional or classic (cPKCs; α, βI, βII, and γ), novel or non-classic (nPKCs; δ, ε, η, and θ), and atypical (aPKCs; ζ, ι, and λ) (PKCλ is the mouse homolog of PKCι) PKC isozymes. PKC isozymes play important roles in proliferation, differentiation, survival, migration, invasion, apoptosis, and anticancer drug resistance in cancer cells. Several studies have shown a positive relationship between PKC isozymes and poor disease-free survival, poor survival following anticancer drug treatment, and increased recurrence. Furthermore, a higher level of PKC activation has been reported in cancer tissues compared to that in normal tissues. These data suggest that PKC isozymes represent potential diagnostic and prognostic biomarkers and therapeutic targets for cancer. This review summarizes the current knowledge and discusses the potential of PKC isozymes as biomarkers in the diagnosis, prognosis, and treatment of cancers.
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Affiliation(s)
- Takahito Kawano
- Center for Advanced Medical Innovation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Junichi Inokuchi
- Department of Urology, Graduate School of Medical Sciences, Kyushu University, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Masatoshi Eto
- Center for Advanced Medical Innovation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
- Department of Urology, Graduate School of Medical Sciences, Kyushu University, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Masaharu Murata
- Center for Advanced Medical Innovation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Jeong-Hun Kang
- Division of Biopharmaceutics and Pharmacokinetics, National Cerebral and Cardiovascular Center Research Institute, 6-1 Shinmachi, Kishibe, Suita, Osaka 564-8565, Japan
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5
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Cooke M, Zhang X, Zhang S, Eruslanov E, Lal P, Daniel RE, Feldman MD, Abba MC, Kazanietz MG. PROTEIN KINASE C ALPHA IS A CENTRAL NODE FOR TUMORIGENIC TRANSCRIPTIONAL NETWORKS IN HUMAN PROSTATE CANCER. CANCER RESEARCH COMMUNICATIONS 2022; 2:1372-1387. [PMID: 36818489 PMCID: PMC9933888 DOI: 10.1158/2767-9764.crc-22-0170] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 08/12/2022] [Accepted: 09/26/2022] [Indexed: 06/18/2023]
Abstract
Aberrant expression of protein kinase C (PKC) isozymes is a hallmark of cancer. The different members of the PKC family control cellular events associated with cancer development and progression. Whereas the classical/conventional PKCα isozyme has been linked to tumor suppression in most cancer types, here we demonstrate that this kinase is required for the mitogenic activity of aggressive human prostate cancer cells displaying aberrantly high PKCα expression. Immunohistochemical analysis showed abnormal up-regulation of PKCα in human primary prostate tumors. Interestingly, silencing PKCα expression from aggressive prostate cancer cells impairs cell cycle progression, proliferation and invasion, as well as their tumorigenic activity in a mouse xenograft model. Mechanistic analysis revealed that PKCα exerts a profound control of gene expression, particularly over genes and transcriptional networks associated with cell cycle progression and E2F transcription factors. PKCα RNAi depletion from PC3 prostate cancer cells led to a reduction in the expression of pro-inflammatory cytokine and epithelial-to-mesenchymal transition (EMT) genes, as well as a prominent down-regulation of the immune checkpoint ligand PD-L1. This PKCα-dependent gene expression profile was corroborated in silico using human prostate cancer databases. Our studies established PKCα as a multifunctional kinase that plays pleiotropic roles in prostate cancer, particularly by controlling genetic networks associated with tumor growth and progression. The identification of PKCα as a pro-tumorigenic kinase in human prostate cancer provides strong rationale for the development of therapeutic approaches towards targeting PKCα or its effectors.
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Affiliation(s)
- Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Medicine, Einstein Medical Center Philadelphia, Philadelphia, Pennsylvania
| | - Xuyao Zhang
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Suli Zhang
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Evgeniy Eruslanov
- Division of Thoracic Surgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Priti Lal
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Reba E. Daniel
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael D. Feldman
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Martin C. Abba
- Centro de Investigaciones Inmunológicas Básicas y Aplicadas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Marcelo G. Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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6
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Cooke M, Kazanietz MG. Overarching roles of diacylglycerol signaling in cancer development and antitumor immunity. Sci Signal 2022; 15:eabo0264. [PMID: 35412850 DOI: 10.1126/scisignal.abo0264] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Diacylglycerol (DAG) is a lipid second messenger that is generated in response to extracellular stimuli and channels intracellular signals that affect mammalian cell proliferation, survival, and motility. DAG exerts a myriad of biological functions through protein kinase C (PKC) and other effectors, such as protein kinase D (PKD) isozymes and small GTPase-regulating proteins (such as RasGRPs). Imbalances in the fine-tuned homeostasis between DAG generation by phospholipase C (PLC) enzymes and termination by DAG kinases (DGKs), as well as dysregulation in the activity or abundance of DAG effectors, have been widely associated with tumor initiation, progression, and metastasis. DAG is also a key orchestrator of T cell function and thus plays a major role in tumor immunosurveillance. In addition, DAG pathways shape the tumor ecosystem by arbitrating the complex, dynamic interaction between cancer cells and the immune landscape, hence representing powerful modifiers of immune checkpoint and adoptive T cell-directed immunotherapy. Exploiting the wide spectrum of DAG signals from an integrated perspective could underscore meaningful advances in targeted cancer therapy.
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Affiliation(s)
- Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Medicine, Einstein Medical Center Philadelphia, Philadelphia, PA 19141, USA
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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7
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Glutathione S-Transferases in Cancer. Antioxidants (Basel) 2021; 10:antiox10050701. [PMID: 33946704 PMCID: PMC8146591 DOI: 10.3390/antiox10050701] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/23/2021] [Accepted: 04/27/2021] [Indexed: 02/06/2023] Open
Abstract
In humans, the glutathione S-transferases (GST) protein family is composed of seven members that present remarkable structural similarity and some degree of overlapping functionalities. GST proteins are crucial antioxidant enzymes that regulate stress-induced signaling pathways. Interestingly, overactive GST proteins are a frequent feature of many human cancers. Recent evidence has revealed that the biology of most GST proteins is complex and multifaceted and that these proteins actively participate in tumorigenic processes such as cell survival, cell proliferation, and drug resistance. Structural and pharmacological studies have identified various GST inhibitors, and these molecules have progressed to clinical trials for the treatment of cancer and other diseases. In this review, we discuss recent findings in GST protein biology and their roles in cancer development, their contribution in chemoresistance, and the development of GST inhibitors for cancer treatment.
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8
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Parker PJ, Lockwood N, Davis K, Kelly JR, Soliman TN, Pardo AL, Marshall JJT, Redmond JM, Vitale M, Silvia Martini. A cancer-associated, genome protective programme engaging PKCε. Adv Biol Regul 2020; 78:100759. [PMID: 33039823 PMCID: PMC7689578 DOI: 10.1016/j.jbior.2020.100759] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 09/27/2020] [Accepted: 10/02/2020] [Indexed: 12/21/2022]
Abstract
Associated with their roles as targets for tumour promoters, there has been a long-standing interest in how members of the protein kinase C (PKC) family act to modulate cell growth and division. This has generated a great deal of observational data, but has for the most part not afforded clear mechanistic insights into the control mechanisms at play. Here, we review the roles of PKCε in protecting transformed cells from non-disjunction. In this particular cell cycle context, there is a growing understanding of the pathways involved, affording biomarker and interventional insights and opportunities.
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Affiliation(s)
- Peter J Parker
- Protein Phosphorylation Laboratory, Francis Crick Institute, London, NW1 1AT, UK; School of Cancer and Pharmaceutical Sciences, Guy's Campus, London, SE1 1UL, UK.
| | - Nicola Lockwood
- Protein Phosphorylation Laboratory, Francis Crick Institute, London, NW1 1AT, UK
| | - Khalil Davis
- Protein Phosphorylation Laboratory, Francis Crick Institute, London, NW1 1AT, UK
| | - Joanna R Kelly
- Cancer Research UK, Manchester Institute, Alderley Park, SK10 4TG, UK
| | - Tanya N Soliman
- Barts Cancer Institute, Charterhouse Square, London, EC1M 6BE, UK
| | - Ainara Lopez Pardo
- Protein Phosphorylation Laboratory, Francis Crick Institute, London, NW1 1AT, UK
| | | | | | - Marco Vitale
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Silvia Martini
- Protein Phosphorylation Laboratory, Francis Crick Institute, London, NW1 1AT, UK
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9
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The PKC universe keeps expanding: From cancer initiation to metastasis. Adv Biol Regul 2020; 78:100755. [PMID: 33017725 DOI: 10.1016/j.jbior.2020.100755] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 02/08/2023]
Abstract
Classical and novel protein kinase C (PKC) isozymes (c/nPKCs), members of the PKC family that become activated by the lipid second messenger diacylglycerol (DAG) and phorbol esters, exert a myriad of cellular effects that impact proliferative and motile cellular responses. While c/nPKCs have been indisputably associated with tumor promotion, their roles exceed by far their sole involvement as promoter kinases. Indeed, this original dogma has been subsequently redefined by the introduction of several new concepts: the identification of tumor suppressing roles for c/nPKCs, and their participation in early and late stages of carcinogenesis. This review dives deep into the intricate roles of c/nPKCs in cancer initiation as well as in the different stages of the metastatic cascade, with great emphasis in their involvement in cancer cell motility via regulation of small Rho GTPases, the production of extracellular matrix (ECM)-degrading proteases, and the epithelial-to-mesenchymal transition (EMT) program required for the acquisition of highly invasive traits. Here, we highlight functional interplays between either PKCα or PKCε and mesenchymal features that may ultimately contribute to anticancer drug resistance in cellular and animal models. We also introduce the novel hypothesis that c/nPKCs may be implicated in the control of immune evasion through the regulation of immune checkpoint protein expression. In summary, dissecting the colossal complexity of c/nPKC signaling in the wide spectrum of cancer progression may bring new opportunities for the development of meaningful tools aiding for cancer prognosis and therapy.
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10
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Liu J, Zheng Y, Gao Y, Quan Z, Qiao B, Li L, Li T, Duan L, Yang J, Luo C, Wu X. Inhibitor 9 Combined With Androgen Deprivation Therapy or Chemotherapy Delays the Malignant Behavior of Castration-Resistant Prostate Cancer Through K-Ras/PLCε/PKCε Signaling Pathway. Front Oncol 2020; 10:75. [PMID: 32158687 PMCID: PMC7051985 DOI: 10.3389/fonc.2020.00075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/15/2020] [Indexed: 12/12/2022] Open
Abstract
Castration-resistant prostate cancer (CRPC) is a progressed stage of prostate cancer, which requires better understanding of the mechanisms and remains an unmet clinical need. As a common oncogene, K-Ras is associated with malignant behavior in different types of tumors but its role in CRPC is unknown. The present study aims to find the mechanism of K-Ras in CRPC and whether it can be used as a crucial molecule for the treatment of CRPC. For this purpose, tissue samples from primary prostate cancer (PPC) and CRPC patients were analyzed by immunohistochemistry and the data showed that K-Ras was elevated in CRPC. More importantly, higher K-Ras expression was related to a shorter recurrence-free survival time in patients with CRPC. In addition, K-Ras promoted the invasion, migration, and drug resistance of CRPC cells by activation of PLCε/PKCε signaling pathway. Meanwhile, the inhibitor of K-RasG12C mutants was able to inhibit malignant behavior of CRPC cells in vitro and in vivo. Inhibitors of K-RasG12C mutants have entered clinical trials. Taken together, the study shows that K-Ras may activate PKCε through PLCε, resulting in the alterations of malignant behavior of CRPC. Inhibitor 9, an inhibitor of the K-RasG12C mutant, has a strong anti-tumor effect in CRPC, which potentially suggests that inhibitors of this nature may serve as a promising treatment for CRPC.
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Affiliation(s)
- Jiayu Liu
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yongbo Zheng
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yingying Gao
- Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, China.,Department of Laboratory Diagnosis, Clinical Medical College, Jiamusi University, Heilongjiang, China
| | - Zhen Quan
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Bo Qiao
- Department of Orthopaedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Luo Li
- Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, China.,Department of Laboratory Diagnosis, Chongqing Public Health Medical Treatment Center, Chongqing, China
| | - Ting Li
- Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, China
| | - Limei Duan
- Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, China
| | - Jinxiao Yang
- Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, China
| | - Chunli Luo
- Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, China
| | - Xiaohou Wu
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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11
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Kazanietz MG, Durando M, Cooke M. CXCL13 and Its Receptor CXCR5 in Cancer: Inflammation, Immune Response, and Beyond. Front Endocrinol (Lausanne) 2019; 10:471. [PMID: 31354634 PMCID: PMC6639976 DOI: 10.3389/fendo.2019.00471] [Citation(s) in RCA: 160] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 06/28/2019] [Indexed: 12/25/2022] Open
Abstract
It is well-established that the chemokine C-X-C motif ligand 13 (CXCL13) and its receptor, the G-protein coupled receptor (GPCR) CXCR5, play fundamental roles in inflammatory, infectious and immune responses. Originally identified as a B-cell chemoattractant, CXCL13 exerts important functions in lymphoid neogenesis, and has been widely implicated in the pathogenesis of a number of autoimmune diseases and inflammatory conditions, as well as in lymphoproliferative disorders. Current evidence also indicates that the CXCL13:CXCR5 axis orchestrates cell-cell interactions that regulate lymphocyte infiltration within the tumor microenvironment, thereby determining responsiveness to cytotoxic and immune-targeted therapies. In this review, we provide a comprehensive perspective of the involvement of CXCL13 and its receptor in cancer progression. Studies in recent years postulated novel roles for this chemokine in controlling the cancer cell phenotype, and suggest important functions in the growth and metastatic dissemination of solid tumors. Carcinogens have been found to induce CXCL13 production, and production of this chemokine within the tumor milieu has been shown to impact the proliferation, migration, and invasive properties of cancer cells. Thus, the complex networks of cellular interactions involving tumoral CXCL13 and CXCR5 integrate to promote cancer cell autonomous and non-autonomous responses, highlighting the relevance of autocrine and paracrine interactions in dictating the cancer phenotype. Dissecting the molecular and signaling events regulated by CXCL13 and how this chemokine dynamically controls the interaction between the cancer cell and the tumor microenvironment is key to identify novel effectors and therapeutic targets for cancer treatment.
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Affiliation(s)
| | | | - Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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12
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Cooke M, Casado-Medrano V, Ann J, Lee J, Blumberg PM, Abba MC, Kazanietz MG. Differential Regulation of Gene Expression in Lung Cancer Cells by Diacyglycerol-Lactones and a Phorbol Ester Via Selective Activation of Protein Kinase C Isozymes. Sci Rep 2019; 9:6041. [PMID: 30988374 PMCID: PMC6465381 DOI: 10.1038/s41598-019-42581-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/29/2019] [Indexed: 02/06/2023] Open
Abstract
Despite our extensive knowledge on the biology of protein kinase C (PKC) and its involvement in disease, limited success has been attained in the generation of PKC isozyme-specific modulators acting via the C1 domain, the binding site for the lipid second messenger diacylglycerol (DAG) and the phorbol ester tumor promoters. Synthetic efforts had recently led to the identification of AJH-836, a DAG-lactone with preferential affinity for novel isozymes (nPKCs) relative to classical PKCs (cPKCs). Here, we compared the ability of AJH-836 and a prototypical phorbol ester (phorbol 12-myristate 13-acetate, PMA) to induce changes in gene expression in a lung cancer model. Gene profiling analysis using RNA-Seq revealed that PMA caused major changes in gene expression, whereas AJH-836 only induced a small subset of genes, thus providing a strong indication for a major involvement of cPKCs in their control of gene expression. MMP1, MMP9, and MMP10 were among the genes most prominently induced by PMA, an effect impaired by RNAi silencing of PKCα, but not PKCδ or PKCε. Comprehensive gene signature analysis and bioinformatics efforts, including functional enrichment and transcription factor binding site analyses of dysregulated genes, identified major differences in pathway activation and transcriptional networks between PMA and DAG-lactones. In addition to providing solid evidence for the differential involvement of individual PKC isozymes in the control of gene expression, our studies emphasize the importance of generating targeted C1 domain ligands capable of differentially regulating PKC isozyme-specific function in cellular models.
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Affiliation(s)
- Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Victoria Casado-Medrano
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jihyae Ann
- Laboratory of Medicinal Chemistry, College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jeewoo Lee
- Laboratory of Medicinal Chemistry, College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, Bethesda, MD, 20892, USA
| | - Martin C Abba
- Centro de Investigaciones Inmunológicas Básicas y Aplicadas, Universidad Nacional de La Plata, CP1900, La Plata, Argentina.
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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13
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Distinctive requirement of PKCε in the control of Rho GTPases in epithelial and mesenchymally transformed lung cancer cells. Oncogene 2019; 38:5396-5412. [PMID: 30923343 PMCID: PMC6609469 DOI: 10.1038/s41388-019-0796-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 12/17/2022]
Abstract
Diacylglycerol (DAG)/phorbol ester-regulated protein kinase C (PKC) isozymes have been widely linked to tumor promotion and the development of a metastatic phenotype. PKCε, an oncogenic member of the PKC family, is abnormally overexpressed in lung cancer and other cancer types. This kinase plays significant roles in proliferation, survival and migration; however its role in epithelial-to-mesenchymal transition (EMT) has been scarcely studied. Silencing experiments in non-small lung cancer (NSCLC) cells revealed that PKCε or other DAG-regulated PKCs (PKCα and PKCδ) were dispensable for the acquisition of a mesenchymal phenotype induced by transforming growth factor beta (TGF-β). Unexpectedly, we found a nearly complete down-regulation of PKCε expression in TGF-β-mesenchymally transformed NSCLC cells. PMA and AJH-836 (a DAG-mimetic that preferentially activates PKCε) promote ruffle formation in NSCLC cells via Rac1, however they fail to induce these morphological changes in TGF-β-mesenchymally transformed cells despite their elevated Rac1 activity. Several Rac Guanine nucleotide Exchange-Factors (Rac-GEFs) were also up-regulated in TGF-β-treated NSCLC cells, including Trio and Tiam2, which were required for cell motility. Lastly, we found that silencing or inhibiting PKCε enhances RhoA activity and stress fiber formation, a phenotype also observed in TGF-β-transformed cells. Our studies established a distinctive involvement of PKCε in epithelial and mesenchymal NSCLC cells, and identified a complex interplay between PKCε and small GTPases that contributes to regulation of NSCLC cell morphology and motile activity.
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14
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Xu W, Zeng F, Li S, Li G, Lai X, Wang QJ, Deng F. Crosstalk of protein kinase C ε with Smad2/3 promotes tumor cell proliferation in prostate cancer cells by enhancing aerobic glycolysis. Cell Mol Life Sci 2018; 75:4583-4598. [PMID: 30209539 PMCID: PMC11105635 DOI: 10.1007/s00018-018-2914-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 08/31/2018] [Indexed: 01/08/2023]
Abstract
Protein kinase C ε (PKCε) has emerged as an oncogenic protein kinase and plays important roles in cancer cell survival, proliferation, and invasion. It is, however, still unknown whether PKCε affects cell proliferation via glucose metabolism in cancer cells. Here we report a novel function of PKCε that provides growth advantages for cancer cells by enhancing tumor cells glycolysis. We found that either PKCε or Smad2/3 promoted aerobic glycolysis, expression of the glycolytic genes encoding HIF-1α, HKII, PFKP and MCT4, and tumor cell proliferation, while overexpression of PKCε or Smad3 enhanced aerobic glycolysis and cell proliferation in a protein kinase D- or TGF-β-independent manner in PC-3M and DU145 prostate cancer cells. The effects of PKCε silencing were reversed by ectopic expression of Smad3. PKCε or Smad3 ectopic expression-induced increase in cell growth was antagonized by inhibition of lactate transportation. Furthermore, interaction of endogenous PKCε with Smad2/3 was primarily responsible for phosphorylation of Ser213 in the Samd3 linker region, and resulted in Smad3 binding to the promoter of the glycolytic genes, thereby promoting cell proliferation. Forced expression of mutant Smad3 (S213A) attenuated PKCε-stimulated protein overexpression of the glycolytic genes. Thus, our results demonstrate a novel PKCε function that promotes cell growth in prostate cancer cells by increasing aerobic glycolysis through crosstalk between PKCε and Smad2/3.
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Affiliation(s)
- Wanfu Xu
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
- Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, China
| | - Fangyin Zeng
- Department of Clinical Laboratory, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou, 510900, China
| | - Songyu Li
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Guihuan Li
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Xiaoju Lai
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Qiming Jane Wang
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Fan Deng
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
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15
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Zhang M, Suarez E, Vasquez JL, Nathanson L, Peterson LE, Rajapakshe K, Basil P, Weigel NL, Coarfa C, Agoulnik IU. Inositol polyphosphate 4-phosphatase type II regulation of androgen receptor activity. Oncogene 2018; 38:1121-1135. [PMID: 30228349 PMCID: PMC6377303 DOI: 10.1038/s41388-018-0498-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 07/05/2018] [Accepted: 08/24/2018] [Indexed: 11/18/2022]
Abstract
Activation and transcriptional reprogramming of AR in advanced prostate cancer frequently coincides with the loss of two tumor suppressors, INPP4B and PTEN, which are highly expressed in human and mouse prostate epithelium. While regulation of AR signaling by PTEN has been described by multiple groups, it is not known whether the loss of INPP4B affects AR activity. Using prostate cancer cell lines we showed that INPP4B regulates AR transcriptional activity and the oncogenic signaling pathways Akt and PKC. Analysis of gene expression in prostate cancer patient cohorts showed a positive correlation between INPP4B expression and both AR mRNA levels and AR transcriptional output. Using an Inpp4b-/- mouse model, we demonstrated that INPP4B suppresses Akt and PKC signaling pathways and modulates AR transcriptional activity in normal mouse prostate. Remarkably, PTEN protein levels and phosphorylation of S380 were the same in Inpp4b-/- and WT males, suggesting that the observed changes were due exclusively to the loss of INPP4B. Our data show that INPP4B modulates AR activity in normal prostate and its loss contributes to the AR-dependent transcriptional profile in prostate cancer.
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Affiliation(s)
- Manqi Zhang
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA
| | - Egla Suarez
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Judy L Vasquez
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | | | - Leif E Peterson
- Center for Biostatistics, Houston Methodist Research Institute, Houston, TX, USA
| | - Kimal Rajapakshe
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Paul Basil
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Nancy L Weigel
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Cristian Coarfa
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Irina U Agoulnik
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA. .,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Biomolecular Science Institute, School of Integrated Science and Humanity, Florida International University, Miami, FL, 33199, USA.
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16
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Garg R, Blando JM, Perez CJ, Lal P, Feldman MD, Smyth EM, Ricciotti E, Grosser T, Benavides F, Kazanietz MG. COX-2 mediates pro-tumorigenic effects of PKCε in prostate cancer. Oncogene 2018; 37:4735-4749. [PMID: 29765153 PMCID: PMC6195867 DOI: 10.1038/s41388-018-0318-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/22/2018] [Accepted: 04/20/2018] [Indexed: 12/31/2022]
Abstract
The pro-oncogenic kinase PKCε is overexpressed in human prostate cancer and cooperates with loss of the tumor suppressor Pten for the development of prostatic adenocarcinoma. However, the effectors driving PKCε-mediated phenotypes remain poorly defined. Here, using cellular and mouse models, we showed that PKCε overexpression acts synergistically with Pten loss to promote NF-κB activation and induce cyclooxygenase-2 (COX-2) expression, phenotypic traits which are also observed in human prostate tumors. Targeted disruption of PKCε from prostate cancer cells impaired COX-2 induction and PGE2 production. Notably, COX-2 inhibitors selectively killed prostate epithelial cells overexpressing PKCε, and this ability was greatly enhanced by Pten loss. Long-term COX-2 inhibition markedly reduced adenocarcinoma formation, as well as angiogenesis in a mouse model of prostate-specific PKCε expression and Pten loss. Overall, our results provide strong evidence for the involvement of the canonical NF-κB pathway and its target gene COX2 as PKCε effectors, and highlight the potential of PKCε as a useful biomarker for the use of COX inhibition for chemopreventive and/or chemotherapeutic purposes in prostate cancer.
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Affiliation(s)
- Rachana Garg
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jorge M Blando
- Department of Immunology, Immunopathology Laboratory, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Carlos J Perez
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, 78957, USA
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
| | - Priti Lal
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael D Feldman
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Emer M Smyth
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Emanuela Ricciotti
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Tilo Grosser
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Fernando Benavides
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, 78957, USA
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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17
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Han T, Zhan W, Gan M, Liu F, Yu B, Chin YE, Wang JB. Phosphorylation of glutaminase by PKCε is essential for its enzymatic activity and critically contributes to tumorigenesis. Cell Res 2018. [PMID: 29515166 PMCID: PMC5993826 DOI: 10.1038/s41422-018-0021-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Glutamine metabolism plays an important role in cancer development and progression. Glutaminase C (GAC), the first enzyme in glutaminolysis, has emerged as an important target for cancer therapy and many studies have focused on the mechanism of enhanced GAC expression in cancer cells. However, little is known about the post-translational modification of GAC. Here, we report that phosphorylation is a crucial post-translational modification of GAC, which is responsible for the higher glutaminase activity in lung tumor tissues and cancer cells. We identify the key Ser314 phosphorylation site on GAC that is regulated by the NF-κB-PKCε axis. Blocking Ser314 phosphorylation by the S314A mutation in lung cancer cells inhibits the glutaminase activity, triggers genetic reprogramming, and alleviates tumor malignancy. Furthermore, we find that a high level of GAC phosphorylation correlates with poor survival rate of lung cancer patients. These findings highlight a previously unappreciated mechanism for activation of GAC by phosphorylation and demonstrate that targeting glutaminase activity can inhibit oncogenic transformation.
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Affiliation(s)
- Tianyu Han
- Institute of Translational Medicine, Nanchang University, Nanchang City, Jiangxi, 330031, China.,School of Life Sciences, Nanchang University, Nanchang City, Jiangxi, 330031, China
| | - Weihua Zhan
- Institute of Translational Medicine, Nanchang University, Nanchang City, Jiangxi, 330031, China.,School of Life Sciences, Nanchang University, Nanchang City, Jiangxi, 330031, China
| | - Mingxi Gan
- Institute of Translational Medicine, Nanchang University, Nanchang City, Jiangxi, 330031, China
| | - Fanrong Liu
- Department of Pathology, The Second Affiliated Hospital of Nanchang University, Nanchang City, Jiangxi, 330006, China
| | - Bentong Yu
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanchang University, Nanchang City, Jiangxi, 330006, China
| | - Y Eugene Chin
- Institute of Health Sciences, Chinese Academy of Sciences at Shanghai, Shanghai, 200025, China
| | - Jian-Bin Wang
- Institute of Translational Medicine, Nanchang University, Nanchang City, Jiangxi, 330031, China.
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18
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Protein Kinase C Epsilon Cooperates with PTEN Loss for Prostate Tumorigenesis through the CXCL13-CXCR5 Pathway. Cell Rep 2017; 19:375-388. [PMID: 28402859 DOI: 10.1016/j.celrep.2017.03.042] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/01/2017] [Accepted: 03/13/2017] [Indexed: 11/22/2022] Open
Abstract
PKCε, an oncogenic member of the PKC family, is aberrantly overexpressed in epithelial cancers. To date, little is known about functional interactions of PKCε with other genetic alterations, as well as the effectors contributing to its tumorigenic and metastatic phenotype. Here, we demonstrate that PKCε cooperates with the loss of the tumor suppressor Pten for the development of prostate cancer in a mouse model. Mechanistic analysis revealed that PKCε overexpression and Pten loss individually and synergistically upregulate the production of the chemokine CXCL13, which involves the transcriptional activation of the CXCL13 gene via the non-canonical nuclear factor κB (NF-κB) pathway. Notably, targeted disruption of CXCL13 or its receptor, CXCR5, in prostate cancer cells impaired their migratory and tumorigenic properties. In addition to providing evidence for an autonomous vicious cycle driven by PKCε, our studies identified a compelling rationale for targeting the CXCL13-CXCR5 axis for prostate cancer treatment.
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19
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Cooke M, Magimaidas A, Casado-Medrano V, Kazanietz MG. Protein kinase C in cancer: The top five unanswered questions. Mol Carcinog 2017; 56:1531-1542. [PMID: 28112438 DOI: 10.1002/mc.22617] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/04/2017] [Accepted: 01/20/2017] [Indexed: 12/29/2022]
Abstract
Few kinases have been studied as extensively as protein kinase C (PKC), particularly in the context of cancer. As major cellular targets for the phorbol ester tumor promoters and diacylglycerol (DAG), a second messenger generated by stimulation of membrane receptors, PKC isozymes play major roles in the control of signaling pathways associated with proliferation, migration, invasion, tumorigenesis, and metastasis. However, despite decades of research, fundamental questions remain to be answered or are the subject of intense controversy. Primary among these unresolved issues are the role of PKC isozymes as either tumor promoter or tumor suppressor kinases and the incomplete understanding on isozyme-specific substrates and effectors. The involvement of PKC isozymes in cancer progression needs to be reassessed in the context of specific oncogenic and tumor suppressing alterations. In addition, there are still major hurdles in addressing isozyme-specific function due to the limited specificity of most pharmacological PKC modulators and the lack of validated predictive biomarkers for response, which impacts the translation of these agents to the clinic. In this review we focus on key controversial issues and upcoming challenges, with the expectation that understanding the intricacies of PKC function will help fulfill the yet unsuccessful promise of targeting PKCs for cancer therapeutics.
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Affiliation(s)
- Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Andrew Magimaidas
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Victoria Casado-Medrano
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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20
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PKCε inhibits isolation and stemness of side population cells via the suppression of ABCB1 transporter and PI3K/Akt, MAPK/ERK signaling in renal cell carcinoma cell line 769P. Cancer Lett 2016; 376:148-54. [PMID: 27037060 DOI: 10.1016/j.canlet.2016.03.041] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 03/12/2016] [Accepted: 03/22/2016] [Indexed: 12/11/2022]
Abstract
Protein kinase C epsilon (PKCε), a member of the novel PKC family, is known to be a transforming oncogene and tumor biomarker for many human solid cancers including renal cell carcinoma (RCC). We isolated side population (SP) cells from the RCC 769P cell line, and proved that those cells possess cancer stem cell (CSC) characteristics. In this study, to identify the function of PKCε in cancer stemness of 769P SP cells, we reduced the expression of PKCε in those cells, following the results demonstrated that PKCε depletion had a negative correlation with the existence of SP cells in 769P cell line. Down-regulation of PKCε also suppresses the CSC potential of sorted 769P SP cells in several ways: proliferation potential, resistance to chemotherapeutics and in vivo tumor formation ability. Our study also reveals that PKCε is associated with ABCB1 and this association probably contributed to the SP cells isolation from 769P cell line. Furthermore, the expression of ABCB1 is directly regulated by PKCε. Additionally, after the depletion of PKCε, the phosphorylation of pAkt, pStat3 and pERK was apparently suppressed in 769P SP cells, whereas PKCε overexpression could promote the phosphorylation of AKT, STAT3 and ERK in 769P Non-SP cells. Overall, PKCε down-regulation suppresses sorting and the cancer stem-like phenotype of RCC 769P SP cells through the regulation of ABCB1 transporter and the PI3K/Akt, Stat3 and MAPK/ERK pathways that are dependent on the phosphorylation effects. Thus, PKCε may work as an important mediator in cancer stem cell pathogenesis of renal cell cancer.
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21
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Toton E, Romaniuk A, Budzianowski J, Hofmann J, Rybczynska M. Zapotin (5,6,2',6'-tetramethoxyflavone) Modulates the Crosstalk Between Autophagy and Apoptosis Pathways in Cancer Cells with Overexpressed Constitutively Active PKCϵ. Nutr Cancer 2016; 68:290-304. [PMID: 26847268 DOI: 10.1080/01635581.2016.1134595] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Autophagy is important in the regulation of survival and death signaling pathways in cancer. PKCϵ revealed high transforming potential and the ability to increase cell migration, invasion, and metastasis. Zapotin (5,6,2',6'-tetramethoxyflavone), a natural flavonoid, showed chemopreventive and anticancer properties. Previously, we reported that downmodulation of induced PKCϵ level by zapotin was associated with decreased migration and increased apoptosis in HeLa cell line containing doxycycline-inducible constitutively active PKCϵ (PKCϵA/E, Ala(159) → Glu). Depending on the genetic and environmental content of cells, autophagy may either precede apoptosis or occur simultaneously. The purpose of this study was to assess the effect of zapotin on autophagy. Increasing concentration of zapotin (from 7.5 µM to 30 µM) caused an inhibition of the formation of autophagosomes and a decline in microtubule-associated protein 1 light chain 3 (LC3) protein levels. The gene expression level of major negative regulator of autophagy was noticeably increased. Moreover, the expression of the pivotal autophagy genes was decreased. These changes were accompanied by alternation in autophagy-related protein levels. In conclusion, our results implied that both the antiautophagic and the proapoptosis effect of zapotin in HeLaPKCϵA/E cells are associated with the protein kinase C epsilon signaling pathway and lead to programmed cell death.
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Affiliation(s)
- Ewa Toton
- a Department of Clinical Chemistry and Molecular Diagnostics , Poznan University of Medical Sciences , Poznan , Poland
| | - Aleksandra Romaniuk
- a Department of Clinical Chemistry and Molecular Diagnostics , Poznan University of Medical Sciences , Poznan , Poland
| | - Jaromir Budzianowski
- b Department of Pharmaceutical Botany , Poznan University of Medical Sciences , Poznan , Poland
| | - Johann Hofmann
- c Biocenter, Division of Medical Biochemistry, Innsbruck Medical University , Innsbruck , Austria
| | - Maria Rybczynska
- a Department of Clinical Chemistry and Molecular Diagnostics , Poznan University of Medical Sciences , Poznan , Poland
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22
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Srivastava J, DiGiovanni J. Non-canonical Stat3 signaling in cancer. Mol Carcinog 2015; 55:1889-1898. [PMID: 26649644 DOI: 10.1002/mc.22438] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/06/2015] [Accepted: 11/09/2015] [Indexed: 01/27/2023]
Abstract
Stat3 is a member of the signal transducers and activators of transcription family and is a known regulator of essential biologic processes including angiogenesis, apoptosis, cell cycle progression, and cell migration. Canonical Stat3-mediated signaling involves tyrosine phosphorylation on specific residues that leads to homodimerization and translocation to the nucleus. For many years it was presumed that most, if not all, of the functions of Stat3, both normal and aberrant, were due to the canonical cytokine and growth factor signaling mechanisms. Recent studies suggest that Stat3 functions through alternate non-canonical pathways to bring about some of these biological functions both in normal cells as well as during cancer development and progression. A number of studies have now shown that Stat3 has a function in mitochondria and that unphosphorylated Stat3 (uStat3) can also function as a transcription factor broadening the potential mechanisms involved in Stat3 action. In this review article, we discuss these two main non-canonical functions of Stat3 and their potential roles in oncogenesis. Given the many facets of Stat3 signaling, additional comprehensive investigations are required to fully understand the role of non-canonical Stat3 signaling in cancer and whether these pathways can be targeted for cancer prevention and treatment. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Jaya Srivastava
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - John DiGiovanni
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
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23
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Gutierrez-Uzquiza A, Lopez-Haber C, Jernigan DL, Fatatis A, Kazanietz MG. PKCε Is an Essential Mediator of Prostate Cancer Bone Metastasis. Mol Cancer Res 2015; 13:1336-46. [PMID: 26023164 DOI: 10.1158/1541-7786.mcr-15-0111] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/20/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED The bone is a preferred site for metastatic homing of prostate cancer cells. Once prostate cancer patients develop skeletal metastases, they eventually succumb to the disease; therefore, it is imperative to identify key molecular drivers of this process. This study examines the involvement of protein kinase C epsilon (PKCε), an oncogenic protein that is abnormally overexpressed in human tumor specimens and cell lines, on prostate cancer cell bone metastasis. PC3-ML cells, a highly invasive prostate cancer PC3 derivative with bone metastatic colonization properties, failed to induce skeletal metastatic foci upon inoculation into nude mice when PKCε expression was silenced using shRNA. Interestingly, while PKCε depletion had only marginal effects on the proliferative, adhesive, and migratory capacities of PC3-ML cells in vitro or in the growth of xenografts upon s.c. inoculation, it caused a significant reduction in cell invasiveness. Notably, PKCε was required for transendothelial cell migration (TEM) as well as for the growth of PC3-ML cells in a bone biomimetic environment. At a mechanistic level, PKCε depletion abrogates the expression of IL1β, a cytokine implicated in skeletal metastasis. Taken together, PKCε is a key factor for driving the formation of bone metastasis by prostate cancer cells and is a potential therapeutic target for advanced stages of the disease. IMPLICATIONS This study uncovers an important new function of PKCε in the dissemination of cancer cells to the bone; thus, highlighting the promising potential of this oncogenic kinase as a therapeutic target for skeletal metastasis.
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Affiliation(s)
- Alvaro Gutierrez-Uzquiza
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cynthia Lopez-Haber
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Danielle L Jernigan
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Alessandro Fatatis
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania. Program in Biology of Prostate Cancer, Sidney Kimmel Cancer Center, Philadelphia, Pennsylvania
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
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24
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Hafeez BB, Fischer JW, Singh A, Zhong W, Mustafa A, Meske L, Sheikhani MO, Verma AK. Plumbagin Inhibits Prostate Carcinogenesis in Intact and Castrated PTEN Knockout Mice via Targeting PKCε, Stat3, and Epithelial-to-Mesenchymal Transition Markers. Cancer Prev Res (Phila) 2015; 8:375-86. [PMID: 25627799 DOI: 10.1158/1940-6207.capr-14-0231] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 01/10/2015] [Indexed: 11/16/2022]
Abstract
Prostate cancer continues to remain the most common cancer and the second leading cause of cancer-related deaths in American males. The Pten deletions and/or mutations are frequently observed in both primary prostate cancers and metastatic prostate tissue samples. Pten deletion in prostate epithelium in mice results in prostatic intraepithelial neoplasia (PIN), followed by progression to invasive adenocarcinoma. The Pten conditional knockout mice [(Pten-loxp/loxp:PB-Cre4(+)) (Pten-KO)] provide a unique preclinical model to evaluate agents for efficacy for both the prevention and treatment of prostate cancer. We present here for the first time that dietary plumbagin, a medicinal plant-derived naphthoquinone (200 or 500 ppm) inhibits tumor development in intact as well as castrated Pten-KO mice. Plumbagin has shown no signs of toxicity at either of these doses. Plumbagin treatment resulted in a decrease expression of PKCε, AKT, Stat3, and COX2 compared with the control mice. Plumbagin treatment also inhibited the expression of vimentin and slug, the markers of epithelial-to-mesenchymal transition (EMT) in prostate tumors. In summary, the results indicate that dietary plumbagin inhibits growth of both primary and castration-resistant prostate cancer (CRPC) in Pten-KO mice, possibly via inhibition of PKCε, Stat3, AKT, and EMT markers (vimentin and slug), which are linked to the induction and progression of prostate cancer.
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Affiliation(s)
- Bilal Bin Hafeez
- Department of Human Oncology, Wisconsin Institute for Medical Research, Paul Carbone Comprehensive Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin.
| | - Joseph W Fischer
- Department of Human Oncology, Wisconsin Institute for Medical Research, Paul Carbone Comprehensive Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Ashok Singh
- Department of Human Oncology, Wisconsin Institute for Medical Research, Paul Carbone Comprehensive Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Weixiong Zhong
- Department of Pathology, Wisconsin Institute for Medical Research, Paul Carbone Comprehensive Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Ala Mustafa
- Department of Human Oncology, Wisconsin Institute for Medical Research, Paul Carbone Comprehensive Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Louise Meske
- Department of Human Oncology, Wisconsin Institute for Medical Research, Paul Carbone Comprehensive Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Mohammad Ozair Sheikhani
- Department of Human Oncology, Wisconsin Institute for Medical Research, Paul Carbone Comprehensive Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Ajit Kumar Verma
- Department of Human Oncology, Wisconsin Institute for Medical Research, Paul Carbone Comprehensive Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
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25
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Garg R, Benedetti LG, Abera MB, Wang H, Abba M, Kazanietz MG. Protein kinase C and cancer: what we know and what we do not. Oncogene 2014; 33:5225-37. [PMID: 24336328 DOI: 10.1038/onc.2013.524] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/20/2013] [Accepted: 10/20/2013] [Indexed: 02/08/2023]
Abstract
Since their discovery in the late 1970s, protein kinase C (PKC) isozymes represent one of the most extensively studied signaling kinases. PKCs signal through multiple pathways and control the expression of genes relevant for cell cycle progression, tumorigenesis and metastatic dissemination. Despite the vast amount of information concerning the mechanisms that control PKC activation and function in cellular models, the relevance of individual PKC isozymes in the progression of human cancer is still a matter of controversy. Although the expression of PKC isozymes is altered in multiple cancer types, the causal relationship between such changes and the initiation and progression of the disease remains poorly defined. Animal models developed in the last years helped to better understand the involvement of individual PKCs in various cancer types and in the context of specific oncogenic alterations. Unraveling the enormous complexity in the mechanisms by which PKC isozymes have an impact on tumorigenesis and metastasis is key for reassessing their potential as pharmacological targets for cancer treatment.
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Affiliation(s)
- R Garg
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - L G Benedetti
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - M B Abera
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - H Wang
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - M Abba
- Centro de Investigaciones Inmunológicas Básicas y Aplicadas (CINIBA), Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - M G Kazanietz
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Wang H, Gutierrez-Uzquiza A, Garg R, Barrio-Real L, Abera MB, Lopez-Haber C, Rosemblit C, Lu H, Abba M, Kazanietz MG. Transcriptional regulation of oncogenic protein kinase Cϵ (PKCϵ) by STAT1 and Sp1 proteins. J Biol Chem 2014; 289:19823-38. [PMID: 24825907 DOI: 10.1074/jbc.m114.548446] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Overexpression of PKCϵ, a kinase associated with tumor aggressiveness and widely implicated in malignant transformation and metastasis, is a hallmark of multiple cancers, including mammary, prostate, and lung cancer. To characterize the mechanisms that control PKCϵ expression and its up-regulation in cancer, we cloned an ∼ 1.6-kb promoter segment of the human PKCϵ gene (PRKCE) that displays elevated transcriptional activity in cancer cells. A comprehensive deletional analysis established two regions rich in Sp1 and STAT1 sites located between -777 and -105 bp (region A) and -921 and -796 bp (region B), respectively, as responsible for the high transcriptional activity observed in cancer cells. A more detailed mutagenesis analysis followed by EMSA and ChIP identified Sp1 sites in positions -668/-659 and -269/-247 as well as STAT1 sites in positions -880/-869 and -793/-782 as the elements responsible for elevated promoter activity in breast cancer cells relative to normal mammary epithelial cells. RNAi silencing of Sp1 and STAT1 in breast cancer cells reduced PKCϵ mRNA and protein expression, as well as PRKCE promoter activity. Moreover, a strong correlation was found between PKCϵ and phospho-Ser-727 (active) STAT1 levels in breast cancer cells. Our results may have significant implications for the development of approaches to target PKCϵ and its effectors in cancer therapeutics.
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Affiliation(s)
- HongBin Wang
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Alvaro Gutierrez-Uzquiza
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Rachana Garg
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Laura Barrio-Real
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Mahlet B Abera
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Cynthia Lopez-Haber
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Cinthia Rosemblit
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Huaisheng Lu
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Martin Abba
- the Centro de Investigaciones Inmunológicas Básicas y Aplicadas, Universidad Nacional de La Plata, CP1900 La Plata, Argentina
| | - Marcelo G Kazanietz
- From the Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
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27
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Mencalha AL, Corrêa S, Abdelhay E. Role of calcium-dependent protein kinases in chronic myeloid leukemia: combined effects of PKC and BCR-ABL signaling on cellular alterations during leukemia development. Onco Targets Ther 2014; 7:1247-54. [PMID: 25045273 PMCID: PMC4099416 DOI: 10.2147/ott.s64303] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Calcium-dependent protein kinases (PKCs) function in a myriad of cellular processes, including cell-cycle regulation, proliferation, hematopoietic stem cell differentiation, apoptosis, and malignant transformation. PKC inhibitors, when targeted to these pathways, have demonstrated efficacy against several types of solid tumors as well as leukemia. Chronic myeloid leukemia (CML) represents 20% of all adult leukemia. The aberrant Philadelphia chromosome has been reported as the main cause of CML development in hematopoietic stem cells, due to the formation of the BCR-ABL oncogene. PKCs and BCR-ABL coordinate several signaling pathways that are crucial to cellular malignant transformation. Experimental and clinical evidence suggests that pharmacological approaches using PKC inhibitors may be effective in the treatment of CML. This mini review summarizes articles from the National Center for Biotechnology Information website that have shown evidence of the involvement of PKC in CML.
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Affiliation(s)
- André L Mencalha
- Biophysics and Biometry Department, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro's State University (UERJ), Rio de Janeiro, Brazil
| | - Stephany Corrêa
- Bone Marrow Transplantation Unit (CEMO), National Cancer Institute (INCA), Rio de Janeiro, Brazil
| | - Eliana Abdelhay
- Bone Marrow Transplantation Unit (CEMO), National Cancer Institute (INCA), Rio de Janeiro, Brazil
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Pysz MA, Hao F, Hizli AA, Lum MA, Swetzig WM, Black AR, Black JD. Differential regulation of cyclin D1 expression by protein kinase C α and ϵ signaling in intestinal epithelial cells. J Biol Chem 2014; 289:22268-83. [PMID: 24914206 DOI: 10.1074/jbc.m114.571554] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Cellular accumulation of cyclin D1, a key regulator of cell proliferation and tumorigenesis, is subject to tight control. Our previous studies have identified PKCα as a negative regulator of cyclin D1 in the intestinal epithelium. However, treatment of non-transformed IEC-18 ileal crypt cells with PKC agonists has a biphasic effect on cyclin D1 expression. Initial PKCα-mediated down-regulation is followed by recovery and subsequent accumulation of the cyclin to levels markedly higher than those seen in untreated cells. Using protein overexpression strategies, siRNA, and pharmacological inhibitors, we now demonstrate that the recovery and hyperinduction of cyclin D1 reflect the combined effects of (a) loss of negative signals from PKCα due to agonist-induced PKCα down-regulation and (b) positive effects of PKCϵ. PKCϵ-mediated up-regulation of cyclin D1 requires sustained ERK stimulation and transcriptional activation of the proximal cyclin D1 (CCDN1) promoter, without apparent involvement of changes in protein stability or translation. PKCϵ also up-regulates cyclin D1 expression in colon cancer cells, through mechanisms that parallel those in IEC-18 cells. Although induction of cyclin D1 by PKCϵ is dependent on non-canonical NF-κB activation, the NF-κB site in the proximal promoter is not required. Instead, cyclin D1 promoter activity is regulated by a novel interaction between NF-κB and factors that associate with the cyclic AMP-response element adjacent to the NF-κB site. The differential effects of PKCα and PKCϵ on cyclin D1 accumulation are likely to contribute to the opposing tumor-suppressive and tumor-promoting activities of these PKC family members in the intestinal epithelium.
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Affiliation(s)
- Marybeth A Pysz
- the Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Fang Hao
- the Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - A Asli Hizli
- the Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Michelle A Lum
- From the Eppley Institute for Research in Cancer and Allied Diseases and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
| | - Wendy M Swetzig
- the Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Adrian R Black
- the Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263From the Eppley Institute for Research in Cancer and Allied Diseases and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
| | - Jennifer D Black
- the Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263From the Eppley Institute for Research in Cancer and Allied Diseases and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
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Jain K, Basu A. The Multifunctional Protein Kinase C-ε in Cancer Development and Progression. Cancers (Basel) 2014; 6:860-78. [PMID: 24727247 PMCID: PMC4074807 DOI: 10.3390/cancers6020860] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/27/2014] [Accepted: 04/01/2014] [Indexed: 12/31/2022] Open
Abstract
The protein kinase C (PKC) family proteins are important signal transducers and have long been the focus of cancer research. PKCɛ, a member of this family, is overexpressed in most solid tumors and plays critical roles in different processes that lead to cancer development. Studies using cell lines and animal models demonstrated the transforming potential of PKCɛ. While earlier research established the survival functions of PKCɛ, recent studies revealed its role in cell migration, invasion and cancer metastasis. PKCɛ has also been implicated in epithelial to mesenchymal transition (EMT), which may be the underlying mechanism by which it contributes to cell motility. In addition, PKCɛ affects cell-extracellular matrix (ECM) interactions by direct regulation of the cytoskeletal elements. Recent studies have also linked PKCɛ signaling to cancer stem cell functioning. This review focuses on the role of PKCɛ in different processes that lead to cancer development and progression. We also discussed current literatures on the pursuit of PKCɛ as a target for cancer therapy.
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Affiliation(s)
- Kirti Jain
- Department of Molecular and Medical Genetics, University of North Texas Health Science Center, Institute for Cancer Research, and Focused on Resources for her Health Education and Research, Fort Worth, TX 76107, USA.
| | - Alakananda Basu
- Department of Molecular and Medical Genetics, University of North Texas Health Science Center, Institute for Cancer Research, and Focused on Resources for her Health Education and Research, Fort Worth, TX 76107, USA.
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30
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Stat3 binds to mtDNA and regulates mitochondrial gene expression in keratinocytes. J Invest Dermatol 2014; 134:1971-1980. [PMID: 24496235 PMCID: PMC4057971 DOI: 10.1038/jid.2014.68] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 09/26/2013] [Accepted: 11/05/2013] [Indexed: 11/24/2022]
Abstract
The nuclear transcription factor Stat3 has recently been reported to have a localized mitochondrial regulatory function. Current data suggest that mitochondrial Stat3 (mitoStat3) is necessary for maximal mitochondrial activity and for Ras-mediated transformation independent of Stat3 nuclear activity. We have previously shown that Stat3 plays a pivotal role in epithelial carcinogenesis. Therefore, the aim of the current study was to determine the role of mitoStat3 in epidermal keratinocytes. Herein, we show that normal and neoplastic keratinocytes contain a pool of mitoStat3. EGF and TPA induce Stat3 mitochondrial translocation mediated through phosphorylation of Stat3 at Ser727. In addition, we report that mitoStat3 binds mitochondrial DNA (mtDNA) and associates with the mitochondrial transcription factor TFAM. Furthermore, Stat3 ablation resulted in an increase of mitochondrial encoded gene transcripts. An increase in key nuclear-encoded metabolic genes, PGC-1α and NRF-1, was also observed in Stat3 null keratinocytes, however no changes in nuclear-encoded ETC gene transcripts or mtDNA copy number were observed. Collectively, our findings suggest a heretofore-unreported function for mitoStat3 as a potential mitochondrial transcription factor in keratinocytes. This mitoStat3-mtDNA interaction may represent an alternate signaling pathway that could alter mitochondrial function and biogenesis and play a role in tumorigenesis.
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Bozeman R, Abel EL, Macias E, Cheng T, Beltran L, DiGiovanni J. A novel mechanism of skin tumor promotion involving interferon-gamma (IFNγ)/signal transducer and activator of transcription-1 (Stat1) signaling. Mol Carcinog 2014; 54:642-53. [PMID: 24464587 DOI: 10.1002/mc.22132] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 12/03/2013] [Accepted: 12/20/2013] [Indexed: 01/14/2023]
Abstract
The current study was designed to explore the role of signal transducer and activator of transcription 1 (Stat1) during tumor promotion using the mouse skin multistage carcinogenesis model. Topical treatment with both 12-O-tetradecanoylphorbol-13-acetate (TPA) and 3-methyl-1,8-dihydroxy-9-anthrone (chrysarobin or CHRY) led to rapid phosphorylation of Stat1 on both tyrosine (Y701) and serine (S727) residues in epidermis. CHRY treatment also led to upregulation of unphosphorylated Stat1 (uStat1) at later time points. CHRY treatment also led to upregulation of interferon regulatory factor 1 (IRF-1) mRNA and protein, which was dependent on Stat1. Further analyses demonstrated that topical treatment with CHRY but not TPA upregulated interferon-gamma (IFNγ) mRNA in the epidermis and that the induction of both IRF-1 and uStat1 was dependent on IFNγ signaling. Stat1 deficient (Stat1(-/-) ) mice were highly resistant to skin tumor promotion by CHRY. In contrast, the tumor response (in terms of both papillomas and squamous cell carcinomas) was similar in Stat1(-/-) mice and wild-type littermates with TPA as the promoter. Maximal induction of both cyclooxygenase-2 and inducible nitric oxide synthase in epidermis following treatment with CHRY was also dependent on the presence of functional Stat1. These studies define a novel mechanism associated with skin tumor promotion by the anthrone class of tumor promoters involving upregulation of IFNγ signaling in the epidermis and downstream signaling through activated (phosphorylated) Stat1, IRF-1 and uStat1.
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Affiliation(s)
- Ronald Bozeman
- Graduate School of Biomedical Sciences, University of Texas MD Anderson Cancer Center, Houston, Texas.,Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Erika L Abel
- Department of Carcinogenesis, Science Park-Research Division, The University of Texas MD Anderson Cancer Center, Smithville, Texas
| | - Everardo Macias
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Tianyi Cheng
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Linda Beltran
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - John DiGiovanni
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas.,Department of Nutritional Sciences, College of Natural Sciences, The University of Texas at Austin, Austin, Texas
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32
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Shiota M, Yokomizo A, Takeuchi A, Imada K, Kashiwagi E, Song Y, Inokuchi J, Tatsugami K, Uchiumi T, Naito S. Inhibition of protein kinase C/Twist1 signaling augments anticancer effects of androgen deprivation and enzalutamide in prostate cancer. Clin Cancer Res 2013; 20:951-61. [PMID: 24352647 DOI: 10.1158/1078-0432.ccr-13-1809] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The progression of prostate cancer to metastatic and castration-resistant disease represents a critical step. We previously showed that the transcription factor Twist1, which promotes epithelial-mesenchymal transition, was involved in castration-resistant progression. Similarly, protein kinase C (PKC) has been implicated in both metastatic progression and castration resistance in prostate cancer. EXPERIMENTAL DESIGN In this study, we aimed to elucidate the role of PKC/Twist1 signaling in castration resistance, and to apply this information to the development of a novel therapeutic concept using PKC inhibitor Ro31-8220 against prostate cancer using various prostate cancer cell lines. RESULTS Androgen deprivation and the next-generation antiandrogen enzalutamide induced PKC activation and Twist1 expression, which were reversed by the PKC inhibitor Ro31-8220. Ro31-8220 suppressed cell proliferation in androgen-dependent prostate cancer LNCaP cells, which was augmented by its combination with androgen deprivation or enzalutamide. The favorable anticancer effects of the combination of Ro31-8220 and enzalutamide were also observed in castration-resistant C4-2 and 22Rv1 cells. Furthermore, PKC phosphorylation was elevated in castration-resistant and enzalutamide-resistant cells compared with their parental cells, leading to persistent sensitivity to Ro-31-8220 in castration- and enzalutamide-resistant cells. CONCLUSIONS Taken together, these findings indicate that PKC/Twist1 signaling contributes to castration resistance as well as enzalutamide resistance in prostate cancer, and suggest that therapeutics targeting PKC/Twist1 signaling, such as PKC inhibitors, represent a promising novel therapeutic strategy for prostate cancer, especially castration-resistant prostate cancer, when combined with enzalutamide.
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Affiliation(s)
- Masaki Shiota
- Authors' Affiliations: Departments of Urology and Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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PKC ε Phosphorylates and Mediates the Cell Membrane Localization of RhoA. ISRN ONCOLOGY 2013; 2013:329063. [PMID: 24191200 PMCID: PMC3804392 DOI: 10.1155/2013/329063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 08/18/2013] [Indexed: 11/17/2022]
Abstract
Protein kinase Cε (PKCε) signals through RhoA to modulate cell invasion and motility. In this study, the multifaceted interaction between PKCε and RhoA was defined. Phosphopeptide mapping revealed that PKCε phosphorylates RhoA at T127 and S188. Recombinant PKCε bound to recombinant RhoA in the absence of ATP indicating that the association between PKCε and RhoA does not require an active ATP-docked PKCε conformation. Activation of PKCε resulted in a dramatic coordinated translocation of PKCε and RhoA from the cytoplasm to the cell membrane using time-lapse fluorescence microscopy. Stoichiometric FRET analysis revealed that the molecular interaction between PKCε and RhoA is a biphasic event, an initial peak at the cytoplasm and a gradual prolonged increase at the cell membrane for the entire time-course (12.5 minutes). These results suggest that the PKCε-RhoA complex is assembled in the cytoplasm and subsequently recruited to the cell membrane. Kinase inactive (K437R) PKCε is able to recruit RhoA to the cell membrane indicating that the association between PKCε and RhoA is proximal to the active catalytic site and perhaps independent of a PKCε-RhoA phosphorylation event. This work demonstrates, for the first time, that PKCε phosphorylates and modulates the cell membrane translocation of RhoA.
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34
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Garg R, Caino MC, Kazanietz MG. Regulation of Transcriptional Networks by PKC Isozymes: Identification of c-Rel as a Key Transcription Factor for PKC-Regulated Genes. PLoS One 2013; 8:e67319. [PMID: 23826267 PMCID: PMC3694964 DOI: 10.1371/journal.pone.0067319] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/16/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Activation of protein kinase C (PKC), a family of serine-threonine kinases widely implicated in cancer progression, has major impact on gene expression. In a recent genome-wide analysis of prostate cancer cells we identified distinctive gene expression profiles controlled by individual PKC isozymes and highlighted a prominent role for PKCδ in transcriptional activation. PRINCIPAL FINDINGS Here we carried out a thorough bioinformatics analysis to dissect transcriptional networks controlled by PKCα, PKCδ, and PKCε, the main diacylglycerol/phorbol ester PKCs expressed in prostate cancer cells. Despite the remarkable differences in the patterns of transcriptional responsive elements (REs) regulated by each PKC, we found that c-Rel represents the most frequent RE in promoters regulated by all three PKCs. In addition, promoters of PKCδ-regulated genes were particularly enriched with REs for CREB, NF-E2, RREB, SRF, Oct-1, Evi-1, and NF-κB. Most notably, by using transcription factor-specific RNAi we were able to identify subsets of PKCδ-regulated genes modulated by c-Rel and CREB. Furthermore, PKCδ-regulated genes condensed under the c-Rel transcriptional regulation display significant functional interconnections with biological processes such as angiogenesis, inflammatory response, and cell motility. CONCLUSION/SIGNIFICANCE Our study identified candidate transcription factors in the promoters of PKC regulated genes, in particular c-Rel was found as a key transcription factor in the control of PKCδ-regulated genes. The deconvolution of PKC-regulated transcriptional networks and their nodes may greatly help in the identification of PKC effectors and have significant therapeutics implications.
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Affiliation(s)
- Rachana Garg
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - M. Cecilia Caino
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Marcelo G. Kazanietz
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- * E-mail:
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35
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p120 catenin is a key effector of a Ras-PKCɛ oncogenic signaling axis. Oncogene 2013; 33:1385-94. [PMID: 23542175 DOI: 10.1038/onc.2013.91] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 01/24/2013] [Accepted: 02/04/2013] [Indexed: 12/18/2022]
Abstract
Within the family of protein kinase C (PKC) molecules, the novel isoform PRKCE (PKCɛ) acts as a bona fide oncogene in in vitro and in vivo models of tumorigenesis. Previous studies have reported expression of PKCɛ in breast, prostate and lung tumors above that of normal adjacent tissue. Data from the cancer genome atlas suggest increased copy number of PRKCE in triple negative breast cancer (TNBC). We find that overexpression of PKCɛ in a non-tumorigenic breast epithelial cell line is sufficient to overcome contact inhibition and results in the formation of cellular foci. Correspondingly, inhibition of PKCɛ in a TNBC cell model results in growth defects in two-dimensional (2D) and three-dimensional (3D) culture conditions and orthotopic xenografts. Using stable isotope labeling of amino acids in a cell culture phosphoproteomic approach, we find that CTNND1/p120ctn phosphorylation at serine 268 (P-S268) occurs in a strictly PKCɛ-dependent manner, and that loss of PKCɛ signaling in TNBC cells leads to reversal of mesenchymal morphology and signaling. In a model of Ras activation, inhibition of PKCɛ is sufficient to block mesenchymal cell morphology. Finally, treatment with a PKCɛ ATP mimetic inhibitor, PF-5263555, recapitulates genetic loss of function experiments impairing p120ctn phosphorylation as well as compromising TNBC cell growth in vitro and in vivo. We demonstrate PKCɛ as a tractable therapeutic target for TNBC, where p120ctn phosphorylation may serve as a readout for monitoring patient response.
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Abstract
Prostate cancer (PCa) remains one of the most prevalent malignancies affecting men in the western world. The etiology for PCa development and molecular mechanisms underlying castration-resistant progression are incompletely understood. Emerging evidence from many tumor systems has shown the existence of distinct subpopulations of stem like-cancer cells termed cancer stem cells (CSCs), which may be involved in tumor initiation, progression, metastasis and therapy resistance. Prostate cancer stem cells (PCSCs) have also been identified using different experimental strategies in distinct model systems. In this brief review, we summarize our current knowledge of normal prostate stem/progenitor cells, highlight recent progress on PCSCs, expound on the potential cell-of-origin for PCa and discuss the involvement of PCSCs in PCa progression and castration resistance. Elucidation of the phenotypic and functional properties and molecular regulation of PCSCs will help us better understand PCa biology and may lead to development of novel therapeutics targeting castration-resistant PCa cells.
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Affiliation(s)
- Xin Chen
- Department of Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX, USA
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37
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Plumbagin, a medicinal plant (Plumbago zeylanica)-derived 1,4-naphthoquinone, inhibits growth and metastasis of human prostate cancer PC-3M-luciferase cells in an orthotopic xenograft mouse model. Mol Oncol 2012; 7:428-39. [PMID: 23273564 DOI: 10.1016/j.molonc.2012.12.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 12/04/2012] [Indexed: 01/06/2023] Open
Abstract
We present here first time that Plumbagin (PL), a medicinal plant-derived 1,4-naphthoquinone, inhibits the growth and metastasis of human prostate cancer (PCa) cells in an orthotopic xenograft mouse model. In this study, human PCa PC-3M-luciferase cells (2 × 10(6)) were injected into the prostate of athymic nude mice. Three days post cell implantation, mice were treated with PL (2 mg/kg body wt. i.p. five days in a week) for 8 weeks. Growth and metastasis of PC-3M-luciferase cells was examined weekly by bioluminescence imaging of live mice. PL-treatment significantly (p = 0.0008) inhibited the growth of orthotopic xenograft tumors. Results demonstrated a significant inhibition of metastasis into liver (p = 0.037), but inhibition of metastasis into the lungs (p = 0.60) and lymph nodes (p = 0.27) was not observed to be significant. These results were further confirmed by histopathology of these organs. Results of histopathology demonstrated a significant inhibition of metastasis into lymph nodes (p = 0.034) and lungs (p = 0.028), and a trend to significance in liver (p = 0.075). None of the mice in the PL-treatment group showed PCa metastasis into the liver, but these mice had small metastasis foci into the lymph nodes and lungs. However, control mice had large metastatic foci into the lymph nodes, lungs, and liver. PL-caused inhibition of the growth and metastasis of PC-3M cells accompanies inhibition of the expression of: 1) PKCε, pStat3Tyr705, and pStat3Ser727, 2) Stat3 downstream target genes (survivin and Bcl(xL)), 3) proliferative markers Ki-67 and PCNA, 4) metastatic marker MMP9, MMP2, and uPA, and 5) angiogenesis markers CD31 and VEGF. Taken together, these results suggest that PL inhibits tumor growth and metastasis of human PCa PC3-M-luciferase cells, which could be used as a therapeutic agent for the prevention and treatment of human PCa.
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Garg R, Blando J, Perez CJ, Wang H, Benavides FJ, Kazanietz MG. Activation of nuclear factor κB (NF-κB) in prostate cancer is mediated by protein kinase C epsilon (PKCepsilon). J Biol Chem 2012; 287:37570-82. [PMID: 22955280 DOI: 10.1074/jbc.m112.398925] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Protein kinase C ε (PKCε) has emerged as an oncogenic kinase and plays important roles in cell survival, mitogenesis and invasion. PKCε is up-regulated in most epithelial cancers, including prostate, breast, and lung cancer. Here we report that PKCε is an essential mediator of NF-κB activation in prostate cancer cells. A strong correlation exists between PKCε overexpression and NF-κB activation status in prostate cancer cells. Moreover, transgenic overexpression of PKCε in the mouse prostate causes preneoplastic lesions that display significant NF-κB hyperactivation. PKCε RNAi depletion or inhibition in prostate cancer cells diminishes NF-κB translocation to the nucleus with subsequent impairment of both activation of NF-κB transcription and induction of NF-κB responsive genes in response to the proinflammatory cytokine tumor necrosis factor α (TNFα). On the other hand, PKCε overexpression in normal prostate cells enhances activation of the NF-κB pathway. A mechanistic analysis revealed that TNFα activates PKCε via a C1 domain/diacylglycerol-dependent mechanism that involves phosphatidylcholine-phospholipase C. Moreover, PKCε facilitates the assembly of the TNF receptor-I signaling complex to trigger NF-κB activation. Our studies identified a molecular link between PKCε and NF-κB that controls key responses implicated in prostate cancer progression.
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Affiliation(s)
- Rachana Garg
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Abstract
The protein kinase C (PKC) family of serine/threonine protein kinases is a heterogeneous group of enzymes receiving and integrating signals involved in both normal melanocyte biology and melanoma pathology. Alterations in PKC enzyme expression and activation contribute to the malignant phenotype of melanoma in both oncogenic and tumor suppressive roles. Delineating the diverse and often context-dependent functions of PKC enzymes in melanocyte/melanoma biology is key to capitalize on these kinases as drug targets. This review summarizes several of the diverse functions of PKC in melanocyte and melanoma biology with a focus on PKC enzyme regulation and function.
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Affiliation(s)
- Mitchell F Denning
- Department of Pathology and the Oncology Institute, Loyola University Chicago, Maywood, IL, USA.
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40
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Hafeez BB, Zhong W, Mustafa A, Fischer JW, Witkowsky O, Verma AK. Plumbagin inhibits prostate cancer development in TRAMP mice via targeting PKCε, Stat3 and neuroendocrine markers. Carcinogenesis 2012; 33:2586-92. [PMID: 22976928 DOI: 10.1093/carcin/bgs291] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Plumbagin (PL), 5-hydroxy-2-methyl-1,4-naphthoquinone, is a quinoid constituent isolated from the roots of the medicinal plant Plumbago zeylanica L. (also known as chitrak). PL has also been found in Juglans regia (English Walnut), Juglans cinerea (whitenut) and Juglans nigra (blacknut). The roots of P. zeylanica have been used in Indian and Chinese systems of medicine for more than 2500 years for the treatment of various types of ailments. We were the first to report that PL inhibits the growth and invasion of hormone refractory prostate cancer (PCa) cells [Aziz,M.H. et al. (2008) Plumbagin, a medicinal plant-derived naphthoquinone, is a novel inhibitor of the growth and invasion of hormone-refractory prostate cancer. Cancer Res., 68, 9024-9032.]. Now, we present that PL inhibits in vivo PCa development in the transgenic adenocarcinoma of mouse prostate (TRAMP). PL treatment (2 mg/kg body weight i.p. in 0.2 ml phosphate-buffered saline, 5 days a week) to FVB-TRAMP resulted in a significant (P < 0.01) decrease in prostate tumor size and urogenital apparatus weights at 13 and 20 weeks. Histopathological analysis revealed that PL treatment inhibited progression of prostatic intraepithelial neoplasia (PIN) to poorly differentiated carcinoma (PDC). No animal exhibited diffuse tumor formation in PL-treated group at 13 weeks, whereas 75% of the vehicle-treated mice elicited diffuse PIN and large PDC at this stage. At 20 weeks, 25% of the PL-treated animals demonstrated diffuse PIN and 75% developed small PDC, whereas 100% of the vehicle-treated mice showed large PDC. PL treatment inhibited expression of protein kinase C epsilon (PKCε), signal transducers and activators of transcription 3 phosphorylation, proliferating cell nuclear antigen and neuroendocrine markers (synaptophysin and chromogranin-A) in excised prostate tumor tissues. Taken together, these results further suggest PL could be a novel chemopreventive agent against PCa.
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Affiliation(s)
- Bilal Bin Hafeez
- Department of Human Oncology, Wisconsin Institute of Medical Research, Paul Carbone Comprehensive Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53792, USA.
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McCubrey JA, Steelman LS, Chappell WH, Abrams SL, Montalto G, Cervello M, Nicoletti F, Fagone P, Malaponte G, Mazzarino MC, Candido S, Libra M, Bäsecke J, Mijatovic S, Maksimovic-Ivanic D, Milella M, Tafuri A, Cocco L, Evangelisti C, Chiarini F, Martelli AM. Mutations and deregulation of Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR cascades which alter therapy response. Oncotarget 2012; 3:954-87. [PMID: 23006971 PMCID: PMC3660063 DOI: 10.18632/oncotarget.652] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 09/17/2012] [Indexed: 02/07/2023] Open
Abstract
The Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR cascades are often activated by genetic alterations in upstream signaling molecules such as receptor tyrosine kinases (RTK). Certain components of these pathways, RAS, NF1, BRAF, MEK1, DUSP5, PP2A, PIK3CA, PIK3R1, PIK3R4, PIK3R5, IRS4, AKT, NFKB1, MTOR, PTEN, TSC1, and TSC2 may also be activated/inactivated by mutations or epigenetic silencing. Upstream mutations in one signaling pathway or even in downstream components of the same pathway can alter the sensitivity of the cells to certain small molecule inhibitors. These pathways have profound effects on proliferative, apoptotic and differentiation pathways. Dysregulation of components of these cascades can contribute to: resistance to other pathway inhibitors, chemotherapeutic drug resistance, premature aging as well as other diseases. This review will first describe these pathways and discuss how genetic mutations and epigenetic alterations can result in resistance to various inhibitors.
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Affiliation(s)
- James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC, USA.
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Rimessi A, Zecchini E, Siviero R, Giorgi C, Leo S, Rizzuto R, Pinton P. The selective inhibition of nuclear PKCζ restores the effectiveness of chemotherapeutic agents in chemoresistant cells. Cell Cycle 2012; 11:1040-8. [PMID: 22333579 DOI: 10.4161/cc.11.5.19520] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The atypical protein kinase C (PKC) isoform zeta (PKCζ) has been implicated in the intracellular transduction of mitogenic and apoptotic signals by acting on different signaling pathways. The key role of these processes in tumorigenesis suggests a possible involvement of PKCζ in this event. PKCζ is activated by cytotoxic treatments, inhibits apoptotic cell death and reduces the sensitivity of cancer cells to chemotherapeutic agents. Here, using pharmacological and DNA recombinant approaches, we show that oxidative stress triggers nuclear translocation of PKCζ and induces resistance to apoptotic agents. Accordingly, chemoresistant cells show accumulation of PKCζ within the nucleus, and a nuclear-targeted PKCζ transfected in tumor cells decreases sensitivity to apoptosis. We thus developed a novel recombinant protein capable of selectively inhibiting the nuclear fraction of PKCζ that restored the susceptibility to apoptosis in cells in which PKCζ was enriched in the nuclear fraction, including chemoresistant cells. These findings establish the importance of PKCζ as a possible target to increase the effectiveness of anticancer therapies and highlight potential sites of intervention.
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Affiliation(s)
- Alessandro Rimessi
- Department of Experimental and Diagnostic Medicine, Section of General Pathology, Interdisciplinary Center for the Study of Inflammation (ICSI), Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
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Inoue T, Ogawa O. Role of signaling transduction pathways in development of castration-resistant prostate cancer. Prostate Cancer 2011; 2011:647987. [PMID: 22110995 PMCID: PMC3197001 DOI: 10.1155/2011/647987] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 08/09/2011] [Indexed: 12/16/2022] Open
Abstract
Almost all patients who succumb to prostate cancer die of metastatic castration-resistant disease. Although docetaxel is the standard treatment for this disease and is associated with modest prolongation of survival, there is an urgent need for novel treatments for castration-resistant prostate cancer (CRPC). Great advances in our understanding of the biological and molecular mechanisms of prostate cancer progression have resulted in many clinical trials of numerous targeted therapies. In this paper, we review mechanisms of CRPC development, with particular focus on recent advances in the understanding of specific intracellular signaling pathways participating in the proliferation of CRPC cells.
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Affiliation(s)
- Takahiro Inoue
- Department of Urology, Graduate School of Medicine, Kyoto University, 54 Kawaharacho Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Osamu Ogawa
- Department of Urology, Graduate School of Medicine, Kyoto University, 54 Kawaharacho Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
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Proteins kinase Cɛ is required for non-small cell lung carcinoma growth and regulates the expression of apoptotic genes. Oncogene 2011; 31:2593-600. [PMID: 21996750 DOI: 10.1038/onc.2011.428] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Protein kinase C (PKC)ɛ, a member of the novel PKC family, has key roles in mitogenesis and survival in normal and cancer cells. PKCɛ is frequently overexpressed in epithelial cancers, particularly in lung cancer. Using a short-hairpin RNA approach, here we established that PKCɛ is required for non-small cell lung carcinoma (NSCLC) growth in vitro as well as tumor growth when inoculated into athymic mice. Moreover, sustained delivery of a PKCɛ-selective inhibitor peptide, ɛV1-2, reduced xenograft growth in mice. Both RNA interference depletion and pharmacological inhibition of PKCɛ caused a marked elevation in the number of apoptotic cells in NSCLC tumors. PKCɛ-depleted NSCLC cells show elevated expression of pro-apoptotic proteins of the Bcl-2 family, caspase recruitment domain-containing proteins and tumor necrosis factor ligands/receptor superfamily members. Moreover, a Gene Set Enrichment Analysis revealed that a vast majority of the genes changed in PKCɛ-depleted cells were also deregulated in human NSCLC. Our results strongly suggest that PKCɛ is required for NSCLC cell survival and maintenance of NSCLC tumor growth. Therefore, PKCɛ may represent an attractive therapeutic target for NSCLC.
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Guo LW, Gao L, Rothschild J, Su B, Gelman IH. Control of protein kinase C activity, phorbol ester-induced cytoskeletal remodeling, and cell survival signals by the scaffolding protein SSeCKS/GRAVIN/AKAP12. J Biol Chem 2011; 286:38356-38366. [PMID: 21903576 DOI: 10.1074/jbc.m111.258830] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The product of the SSeCKS/GRAVIN/AKAP12 gene ("SSeCKS") is a major protein kinase (PK) C substrate that exhibits tumor- and metastasis-suppressing activity likely through its ability to scaffold multiple signaling mediators such as PKC, PKA, cyclins, calmodulin, and Src. Although SSeCKS and PKCα bind phosphatidylserine, we demonstrate that phosphatidylserine-independent binding of PKC by SSeCKS is facilitated by two homologous SSeCKS motifs, EG(I/V)(T/S)XWXSFK(K/R)(M/L)VTP(K/R)K(K/R)X(K/R)XXXEXXXE(E/D) (amino acids 592-620 and 741-769). SSeCKS binding to PKCα decreased kinase activity and was dependent on the two PKC-binding motifs. SSeCKS scaffolding of PKC was increased in confluent cell cultures, correlating with significantly increased SSeCKS protein levels and decreased PKCα activity, suggesting a role for SSeCKS in suppressing PKC activation during contact inhibition. SSeCKS-null mouse embryo fibroblasts displayed increased relative basal and phorbol ester (phorbol 12-myristate 13-acetate)-induced PKC activity but were defective in phorbol 12-myristate 13-acetate-induced actin cytoskeletal reorganization and cell shape change; these responses could be rescued by the forced expression of full-length SSeCKS but not by an SSeCKS variant deleted of its PKC-binding domains. Finally, the PKC binding sites in SSeCKS were required to restore cell rounding and/or decreased apoptosis in phorbol ester-treated LNCaP, LNCaP-C4-2, and MAT-LyLu prostate cancer cells. Thus, PKC-mediated remodeling of the actin cytoskeleton is likely regulated by the ability of SSeCKS to control PKC signaling and activity through a direct scaffolding function.
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Affiliation(s)
- Li-Wu Guo
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Lingqiu Gao
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Julian Rothschild
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Bing Su
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Irwin H Gelman
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263.
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Knudsen KE. A tale of three PKCs: epsilon emerges as a driver of pre-neoplastic phenotypes. Cell Cycle 2011; 10:379. [PMID: 21270526 PMCID: PMC3685614 DOI: 10.4161/cc.10.3.14740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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